Arizona Auto Loan Calculator (with Arizona Sales Tax & Fees)

Arizona taxes vehicle purchases differently than most states. Instead of a flat statewide sales tax, dealers collect the Transaction Privilege Tax (TPT) on the retail sale, and Arizona's Motor Vehicle Division (MVD, part of ADOT) applies the state-level 5.6% rate at the point of title and registration. This calculator models that 5.6% state rate against the full negotiated vehicle price, adds a flat $350 estimate for title, registration, and dealer documentation fees, then finances whatever remains after the buyer's cash down payment and trade-in credit.

Arizona car buyers routinely underestimate their out-the-door price because the 5.6% figure quoted online is only the state's share. Maricopa County, Pima County, and most incorporated cities layer on additional county excise and municipal TPT, which is why a car advertised with "6.6% sales tax" in a Phoenix dealership brochure is not wrong, it is simply quoting the combined rate rather than the state baseline this tool uses. Buyers cross-shopping between counties, or comparing a private-party purchase to a dealer purchase, need to understand which rate applies to their transaction before trusting a single monthly payment figure.

This calculator exists to isolate the mechanics that are stable and quotable: the state TPT rate, a standard fee estimate, and a standard amortization schedule. It is built for a shopper who wants to know, before walking into a dealership, roughly what a $35,000 vehicle will actually cost to finance once Arizona's tax structure is applied, not a generic national average.

The engine runs four steps in sequence:

1. Sales tax base. Arizona TPT is applied to the full vehicle purchase price (this calculator does not currently net out a trade-in allowance from the taxable base, since trade-in tax credit rules vary by dealer and transaction type in Arizona). Tax = Vehicle Price x 5.6%.
2. Fee estimate. A flat $350 is added to represent MVD title fees, registration fees, and typical dealer documentation charges.
3. Financed amount. Total Vehicle Cost = Vehicle Price + Sales Tax + Fees. Financed Amount = Total Vehicle Cost - Down Payment (floored at zero).
4. Amortization. The financed amount is amortized as a standard fixed-rate installment loan using the annuity payment formula:

$$PMT = \frac{P \times i}{1 - (1 + i)^{-n}}$$

where P is the financed amount, i is the monthly rate (APR / 12), and n is the loan term in months. Each period's interest is the outstanding balance times i; the remainder of the fixed payment reduces principal.

Using the calculator's own baseline inputs, which match its published test vector:

• Vehicle Purchase Price: $35,000
• Down Payment & Trade-in: $5,000
• Loan Term: 60 months
• Interest Rate (APR): 7.25%

Step by step: - Arizona sales tax: $35,000 x 5.6% = $1,960.00 - Title/registration/doc fees: $350.00 - Total vehicle cost: $35,000 + $1,960 + $350 = $37,310.00 - Financed amount: $37,310 - $5,000 = $32,310.00 - Monthly rate: 7.25% / 12 = 0.604167% per month - Monthly payment: $643.59 - Total interest paid over 60 months: $6,305.67

Doubling the down payment to $10,000 would lower the financed amount to $27,310 and the payment to roughly $545/month, illustrating how sensitive Arizona auto loan payments are to trade-in equity given the tax is charged on the full price regardless of down payment size.

• County and city TPT add-ons. This calculator applies only the 5.6% state rate. Maricopa, Pima, and other counties add their own excise tax, and many cities add a municipal TPT on top of that, pushing the real combined rate to 6.6%-8.8% depending on jurisdiction.
• Vehicle License Tax (VLT). Arizona charges an annual VLT based on 60% of the manufacturer's base retail price, depreciated 16.25% per year, which is separate from sales tax and separate from this loan calculation. It is paid annually at registration renewal, not financed into the loan.
• Trade-in tax offset nuances. Some Arizona transactions allow a trade-in to reduce the taxable base; this calculator taxes the full purchase price and does not model that offset.
• Lender-specific APR variation. Credit unions, captive finance arms (like a manufacturer's own financing), and buy-here-pay-here lots price risk very differently; the APR here is a user input, not a market quote.
• Extended warranties, GAP insurance, and add-ons. Aftermarket products sold at signing are not included in the financed amount.

• Comparing a quoted "5.6% tax" price to a dealer's out-the-door number. The dealer's number almost always includes county and city TPT, so it will be higher than this calculator's estimate unless you manually add your local rate.
• Forgetting the VLT is a recurring annual cost, not a one-time fee rolled into the loan, which trips up first-time Arizona vehicle owners who budget only for the sales tax.
• Financing negative equity from a trade-in without realizing it inflates the principal and therefore the total interest paid over the full term.
• Assuming a lower APR quote from an out-of-state lender applies locally without checking Arizona-specific title and lien recording requirements, which can add processing time and fees.
• Ignoring that private-party sales are still taxed in Arizona at registration, even though no dealer collected it at the point of sale.

• Arizona Department of Revenue, Transaction Privilege Tax (TPT) rate tables for vehicle sales
• Arizona Department of Transportation, Motor Vehicle Division (MVD): title, registration, and Vehicle License Tax guidance
• Consumer Financial Protection Bureau (CFPB): Truth in Lending Act (Regulation Z) disclosure requirements for installment credit
• Tax Foundation: state and local combined sales tax rate comparisons